414 FOODS AND FOOD ADULTERANTS. 



The coloring principle, termed gossypin, is collected on a filter, carefully washed 

 to remove any trace of acid, and dried slowly at a low temperature. It is then ready 

 for use as a dye, and gives fast colors on both silk and wool. It is claimed that tho 

 quantity of coloring matter in a ton of crude oil is 15 pounds, though this pro- 

 portion must vary considerably. Its properties are insolubility in acids, slight solu- 

 bility in water, free solubility in alcohol or alkalies. In its dry state it is a light 

 powder of a pungent odor, of a brown color, and strongly tinctorial. 



Crude cotton-seed is thickly fluid, twenty-eight to thirty times less fluid than water, 

 and has a specific gravity of 0.9283 at 03 F., 0.0806 at 59 F., and 0.9343 at 50 F. 



According to the quality of the oil, palrnitin is separated between 54 and 43 F. 

 The oil congeals at 28.5 to 27 F. In taste and odor it resembles linseed oil, and as 

 regards other properties it is an intermediate between drying and non-drying oils. 



Refined cotton-seed oil has a specific gravity of 0.9264 at 59 F. ; it separates pal- 

 mitin already below 53.5 F., and congeals at 32 to 30 F. 



The oil consists of palmitin and oleiu, and to make it still more adapted for the 

 adulteration of olive oil, for which immense quantities are used every year, it is inten- 

 tionally cooled for the separation of palmitin, which lowers the specific gravity. 



MIXING. 



The term refined lard has long been used to designate a lard coin- 

 posed chiefly of cotton oil and stearine. The largest manufacturers of 

 tbiskind of lard have now abandoned this term and are using the label 

 "lard compound" instead. This is but just to the consumers of this 

 article who are likely to bo misled by the term refined lard. Tho prime 

 steam lard in a state of fusion, the stearine also in a liquid condition, 

 and the refined cotton oil are measured in the proportions to be used and 

 placed in a tank at a temperature of 120 to 1GO F. In this tank the 

 ingredients are thorough ly mixed by means of paddles operated by 

 machinery. After mixing the compound lard passes at once to art iti 

 cial coolers where it is chilled as soon as possible. It is thence run di- 

 rectly into small tin cans or large packages and prepared for market. 



(4) PROPERTIES OF PURE LARD. 

 A. PHYSICAL PROPERTIES. 



(a) Specific gravity. The specific gravity of a pure lard varies rap- 

 idly with the temperature. It is not convenient to take the specific 

 gravity of a lard at a lower temperature than 35 or 40,* inasmuch ;is 

 below that temperature solidification is apt to begin. Tho specific. 

 gravity, therefore, is usually takon at 35 or 40 or at the temperature 

 of boiling water, viz, 100. At 40 the specific gravity of pure lard is 

 about .890, and at 100 about .800, referred to water at 4. 



The specific gravity of pure lard docs not differ greatly from that of 

 many of tho substances used in adulterating it, but it is distinctly lower 

 than that of cotton oil, and is of great distinctive value in analysis. 



(b) Melting point. The melting point of a pure lard is a physical 



' All degrees are Centigi -uln unless otherwise st.-itrd. 



